Trigger a Kubernetes Deployment from a Docker Hub Push Event

Learn how to trigger a Kubernetes deployment when an image is updated

In this example, we will cover how to trigger a Kubernetes deployment from a Docker Hub Push event using a Dockerhub registry trigger.

Our example has two pipelines: one for packaging code (CI), and the second for deploying code (CD).

Prerequisites

Example Project

You can see the example project on GitHub. The repository contains a simple Hello World NodeJs app as well as 2 pipelines.

Create the CI Pipeline

As mentioned before, our first pipeline will handle the CI process.
The pipeline has three stages:

  • A stage for cloning
  • A stage for building the image
  • A stage for pushing the image to DockerHub

Codefresh UI CI Pipeline View

Codefresh UI CI Pipeline View

codefresh-CI-pipeline.yml

version: '1.0'

stages:
- checkout
- build
- push

steps:
  clone:
    title: Cloning main repository...
    type: git-clone
    stage: checkout
    arguments:
      repo: 'codefresh-contrib/registry-trigger-sample-app'
      revision: 'master'
      git: github
  build_my_app:
    title: Building image...
    type: build
    stage: build
    arguments:
      image_name: registry-trigger-sample-app
      working_directory: ${{clone}}
      tag: 'master'
      dockerfile: Dockerfile
  push_to_my_registry:
    stage: 'push'
    type: push
    title: Pushing to Dockerhub...
    arguments:
      candidate: ${{build_my_app}}
      tag: 'latest'
      registry: dockerhub
      image_name: annabaker/registry-trigger-sample-app

This pipeline does the following:

  1. Clones the source code through a Git clone step.
  2. Builds a docker image tagged with the Application version through a build step.
  3. Pushes the Docker image through a push step to the Docker Hub registry you have integrated with Codefresh.

Create the CD Pipeline

This pipeline contains one stage/step, for deploying.

Codefresh UI CD Pipeline View

Codefresh UI CD Pipeline View

Note that for the trigger mechanism to take place, you will need to add a Docker Hub registry trigger to the pipeline.

codefresh-CD-pipeline.yml

version: "1.0"

stages:
  - "deploy"

steps:
  deploy_to_k8s:
    title: Running Deploy Script...
    type: deploy
    kind: kubernetes
    arguments:
      cluster: anna-demo@FirstKubernetes
      namespace: default
      service: registry-trigger-sample-app
      candidate:
        image: annabaker/registry-trigger-sample-app:latest
        registry: 'dockerhub'

This pipeline does the following:

  1. Deploys the image to Kubernetes through a deploy step. The deploy step uses a Registry trigger to kick off the pipeline when the updated image is pushed to the registry.

CD pipeline examples
Codefresh YAML for pipeline definitions
Creating pipelines
How Codefresh pipelines work
Triggers in pipelines